code: def accuracy(output, target, topk=(1,), exact=False):
      """
      Computes the top-k accuracy for the specified values of k
  
      Args:
          output (ch.tensor) : model output (N, classes) or (N, attributes)
              for sigmoid/multitask binary classification
          target (ch.tensor) : correct labels (N,) [multiclass] or (N,
              attributes) [multitask binary]
          topk (tuple) : for each item "k" in this tuple, this method
              will return the top-k accuracy
          exact (bool) : whether to return aggregate statistics (if
              False) or per-example correctness (if True)
  
      Returns:
          A list of top-k accuracies.
      """
      with ch.no_grad():
          # Binary Classification
          if len(target.shape) > 1:
              assert (
                  output.shape == target.shape
              ), "Detected binary classification but output shape != target shape"
              return [
                  ch.round(ch.sigmoid(output))
                  .eq(ch.round(target))
                  .float()
                  .mean()
              ], [-1.0]
  
          maxk = max(topk)
          batch_size = target.size(0)
  
          _, pred = output.topk(maxk, 1, True, True)
          pred = pred.t()
          correct = pred.eq(target.view(1, -1).expand_as(pred))
  
          res = []
          res_exact = []
          for k in topk:
              correct_k = correct[:k].reshape(-1).float()
              ck_sum = correct_k.sum(0, keepdim=True)
              res.append(ck_sum.mul_(100.0 / batch_size))
              res_exact.append(correct_k)
  
          if not exact:
              return res
          else:
              return res_exact
  
imports: import torch
  import shutil
  import dill
  import os
  from subprocess import Popen, PIPE
  import pandas
  from PIL import Image
  from .None import constants
label_desc: Use image node_id 4 for calling a global function with example usage: accuracy(output, target, topk, exact) and returns: list,  list, res, res_exact